A method of hydraulic fracturing of formation (HFF) consists in high pressure pumping a fluid into oil- and gas-bearing formations, thus facilitating the creation of fractures in the formation through which the oil or gas is flowing. To prevent the fracture healing, hard particles, generally, spherical pellets/granules called as proppants that fill the created fractures together with the carrier fluid, are admixed into the fluid being pumped. The proppants should withstand high formation pressures, be resistive to aggressive environments, and retain the physical and mechanical properties at high temperatures. Meanwhile, the proppant should have a density close to the carrier fluid density in order to be present in the fluid in suspended state and to be delivered to most remote fracture sites. Taking into account that water is most frequently used as the fluid for hydraulic fracturing, the proppant density should be close to the water density.
Mineral materials of the natural origin, such as bauxites, kaolins and sands, are frequently used as an initial material for the production of proppants (U.S. Pat. Nos. 4,068,718 and 4,668,645).
It is known to use various materials, such as a borosilicate or calcinated glass, ferrous and non-ferrous metals or alloys thereof, metal oxides, oxides, nitrides and carbides of silicon, for the production of proppants having a shape of hollow pellets (US patent application No. 2012/0145390).
Disadvantages of these materials are a high technological complexity of production of the hollow pellets therefrom, their insufficient compression strength due to the hollow structure and the material fragility, a high degree of proppant breakdown in fractures, and a reverse carry-over of particles and their fragments.
Technical solutions for the production of proppants with a polymeric coating are aimed at the removal of such disadvantages. Such cover works as a compensator of point stresses, thereby more uniformly distributing the pressure throughout the proppant surface and volume, and, moreover, reduces the average proppant density. Widely known is the use of various organic polymeric and non-organic proppant coatings in the form of epoxy and phenol resins (US patent applications Nos. 2012/0205101, 2012/247335).
Disadvantages of these technical solutions are the complexity of producing such proppants, insufficient thermal resistance of the coatings, low ovality and sphericity factors due to the shape of mineral proppant core, and a high spread of physical and mechanical characteristics.
It is known to use a wide spectrum of thermosetting polymers with cross-linkages such as epoxy, vinyl and phenol compounds, polyurethane, polyester, melamine, etc., as the material for producing proppants (US patent application No. 2013/0045901).
Known is the use of polyamide as the material for producing proppants (U.S. Pat. No. 7,931,087).
A disadvantage of the known materials is an inconformity of physical and mechanical properties of these materials simultaneously with the entire combination of requirements applicable to proppant materials. For instance, this is referred to an insufficient resistance to aggressive environments, an insufficient thermal resistance and thermal strength, degree of swelling in liquid hydrocarbons media, compression strength.
A closest technical solution to the proposed one is the use of polydicyclopentadiene as the material for proppant (RU patent No. 2386025).
Disadvantage of the use of polydicyclopentadiene is an insufficient temperature resistance and compression strength and an insufficient oil resistance.